Fountain pen ink reservoir



May 10, 1960 H, E MORSE ETAL 2,935,970

FOUNTAIN PEN INK RESERVOIR Filed March 23, 1955 Ew.- H..

wmv NW m.

El Hl TN EN MNM, Wmv om.. um,

TIN E vm, m,

inited States `aten't FoUNrAm PEN INK RESERVOIR Henry' E. Morse, Norelv A.. Nelson, and Clifford H.

Springer, Holland, Mich., assignors to Sapphire Preducts, Incorporated, Holland, Mich., a corporation of Michigan' Application March 23, 1955, Serial YNo. 496,165

Claims. (Cl. 12th-52) This invention relates to fountain pens and particularly to an improved reservoir means for accumulating ink discharged from the ink Storage chamber during a flooding condition of the pen.

Fountain pens comprise generally a writing element and an ink storage chamber, with a connection for feeding ink to the writing element from the storage chamber. iln manyof the commercial fountain pens of today the storage chamber comprises a rubber sac or the like. An air inlet for the storagechamber is also, provided whereby, asV the ink is expended from the chamber `in Writing, air enters the chamber to replace the expended ink. When the chamber is partially full of ink and partially full of air, theV ink will ilow out of the chamber toward the writing element if the air pressure inthe chamber exceeds the ambient atmospheric pressure. When this differential in air pressure exists, the pen is said to be in a flooding condition. Means have been provided, as disclosed in the prior art, for absorbing this ink forced out of the storage chamber, thereby to prevent the pen from leaking;

With the advent of commercially vsuccessful replaceable ink cartridge type fountain pens which have a much greater ink storage capacity than the conventional ink sac type pens of the same size, itrhas become necessary to provide meansv for absorbing the much greater amounts of ink which tend to llood from the ink storage compartment when a ilooding condition exists in the pen. While the improved overflow ink accumulating reservoir herein disclosed is particularlysuited for pens employing the large capacity replaceable ink cartridge, it is to be understood that it maybe as Well applied to ink sac type pens or the like.

Some o-f the prior art ink absorbing overllow devices have taken the form of a plurality of closely spaced cells of capillary dimension which have been formed either in the ink feed bar of the pen, or aroundthe ink feed bar, or as disclosed in the patent of Wing, 2,282,840, disposed inside the feed bar. A primaryy disadvantage of these prior art devices is their inefficiency in operation in that they do not always empty completely when the conditions return from which the original flooding started. For example, if the air pressure inside and outside the ink storage compartment is equal and the overflow abi sorbing device is empty, and thereafter the air pressure in the storage compartment rises so that it exceeds the ambient atmospheric vair pressure, the pen Will'llood and ink will enter the overllow device. If the air pressure in the pen is thereafter reduced to the same pressure as before the increase (the ambient atmospheric pressure remaining constant), the ink in the overflow device should completely empty back into the storage compartment. However, this does not always occur. overllow device has not completelyA emptied-and the cycle is again. repeated and again not all of the ink which llooded outf of the storage compartment returns to the storagexcompartment; the overllow device will contain anf'increased amountl ofink. It isapparent that if this If the i 2 cycle is repeated often, the overflow device eventually will be filled completely with ink, with the result that upon the next cycle the pen will leak.

Another disadvantage of the prior art overilow ink accumulatore becomes apparent upon attempting to adapt them for use with a replaceable cartridge type pen. This disadvantage is that they are not of a large enough capacity to accommodate the flooding from the larger volume replaceable ink cartridge. Because the replaceable ink cartridge pen holds a greater volume of ink than the sac type pen or the like, there is also a greater volume of airthat accumulates in the storage chamber as the ink is expended. This greater volume of air will cause more ink to flood out of the storage compartment upon the occurrence of a differential in air pressure between the storage compartment and the atmosphere, than in the sac type pen.

When a flooding condition exists in a fountain pen, there are two possible avenues for the escape of the ink from the storage compartment. One of these avenues is for-the ink to pass through the feed'duct between the ink storage compartment and the writing element. The other avenue of escape is along the air intake vent to the storage compartment. In the prior art the plurality of cellsabove mentioned have been disposed in communication with the ink feed duct between lthe ink storage compartment and the writing element. For example, in the patent to Wing above noted, the closely spaced plurality of cells are` disposed beneath the ink feed' duct and in communication therewith. The air intake for the storage compartment passes through these cells and enters the feed duct. When the cells are full or partially full of ink and the pen is used for writing, the ink is supposed to empty from the cells before any air enters the storage sirable to be able to block the passage of air to the storage compartment as long as there is any ink in any overilow in'k accumulator that may be formed in the pen, so that ink ydisposed'in the accumulator will be first exhausted before ink flows out of the storage compartment.

An object of our invention is the provision in a foune tain pen of along continuous air intake passageway opening directly into the ink storage compartmentpwhich long passageway will serve as an overflow ink reservoir for ink forced out of the storage compaitment, with ink in the air intake passage blocking the admission of air to the compartment until all of the ink inthe passageway has emptied back into the compartment. Y

Another object of the invention is the provision in a fountain pen of an air intake line of capillary dimension for the storage chamber and which is of greater cross sectional area than the ink feed duct from the storage chamber tothe writing element, and which line opens at one end into the storage chamber and at its other end outwardly of the pen into the atmosphere.

Another object of the invention is the provision in a fountain pen of a pair of ink reservoirs for accumulating overflow ink from the ink storage compartment, one of which reservoirs accumulates ink flowing through the feed duct from the storage compartment to the writing element, and the other of which accumulates ink flowing directly out of the storage compartment through the air intake line.

Another object of the invention is the provision in a fountain pen of` a pair of' reservoirs, one of whichV is adapted to accumulate ink forced out of the storage compartment by an increase of air pressure therein and which ink flows to the pen nib, with the other reservoir forming the air intake line for the storage compartment and being adapted to hold a greater amount of overflow ink than the first mentioned reservoir.

Still another object of the invention is the provision in a fountain pen of an overflow ink accumulating reservoir which comprises a helical channel of capillary dimension encircling the ink feed duct between the ink storage compartment and the writing element, and which reservoir is formed in a member disposed within the body of the pen between the ink storage compartment and the feed bar of the pen and is adapted to support the feed duct extending between the ink storage compartment and the writing element.

Other objects, advantages, and meritorious features will more fully appear from the specification, claims and accompanying drawings, wherein:

Fig. 1 is a longitudinal cross sectional view through a pen embodying our improved overflow ink reservoir;

Fig. 2 is a cross sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a cross sectional view taken on the line 3-3 of Fig. 1;

Fig. 4 is a cross sectional view taken on the line 4 4 of Fig. 1;

Fig. 5 is a cross sectional view on the line 5--5 of Fig. l;

Fig. 6 is a cross sectional view taken on the line 6-6 of Fig. l.

We have shown in Figs. 1-6, for illustrative purposes only, a fountain pen embodying one form of our invention. The pen shown in Figs. 1-6 is `of the replaceable ink cartridge type. It includes a pen body 20, internally threaded as at 22, to threadedly engage the handle or upper pen body 24 of the pen. The handle or upper pen body is hollow to provide an ink storage compartment 26. The handle itself serves as the replaceable cartridge of the pen. An insert 28, received and secured in any convenient manner within the lower end of the cartridge, is threaded to engage with the threads 22 of the lower pen body, to secure the cartridge to the body. It is to be understood that the invention disclosed herein is not restricted in its application only to pens of the replaceable cartridge type, but may be incorporated as well in other types of pens.

Seated within the bore 30 of the insert 28, and disposed against the shoulder 32 thereof, is a puncturable plug 34. The plug is adapted to be punctured by the threaded point 36 of the pierce 38, when the cartridge and lower pen body are secured together. The operation and construction of the pierce are set forth in greater detail in the co-pending application of Morse et al., Serial No. 408,105, filed February 4, 1954, now Patent No. 2,826,- 174, issued March 1l, 1958. The pierce 38 is shaped as shown in Fig. l, and is received in a snug fit as at 39 within the lower pen body. Spaced from the end of the point 36 is a pair of cross apertures 40 and 42 which open into the passage 44 within the pierce.

Received within the forward end of the pierce in a snug fit, and disposed for the greater pontion of its length in the bore 46 of the pen body 20 in a snug fit, is the primary ink reservoir 48 more fully described hereinafter. The reservoir is provided with an axially extending aperture 50, through which in a snug ink sealing fit extend'the elements 52 and 52-a of an ink feed channel, which elements, for convenience, are termed a sandwich feed.

An ink feed bar 54 is received within the forward end of the pen body 20. A writing element or nib 56, overlying the nib supporting surface 58 of the feed bar, is gripped between the feed bar and the pen body. The feed bar is provided with a sandwich feed receiving slot 60, opening through the rear of the feed bar and upwardly through the nib supporting surface thereof. The sandwich feed extends at its rear end into the passage 44 of the pierce, and extends at its forward end into the slot 60 of the feed bar, and is held up against the writing element by the spring 63 which is disposed within slot 60 beneath the sandwich feed.

The sandwich feed is more fully described in the copending application of Morse et al., Serial No. 500,755 filed April 12, 1955. The members 52 and 52-a forming the sandwich feed are juxtaposed as shown in Figs. 1-6, with member 52 provided with a longitudinal channel 62 opening toward the meeting faces of the members. At opposite sides of channel 62, the meeting faces of members 52 and 52-a define therebetween, as at 64 and 66, ink film passages. The channel `62 is of capillary size and communicates with the ink film passages 64 and 66 which are also of capillary dimension, throughout the length of the sandwich feed. Member 52 is provided, as shown in Figs. 1 and 6, with an upwardly opening slot 68 and 70 at each end. The nib 56 is provided with an ink feed slit 72 which registers with the slot 68 in the forward end of member 52.

Ink in the storage compartment enters the sandwich feed by passing through the cross apertures 40 and 42 in the point 36 of the pierce, and thence through the slot 70. It enters passages 64 and 66 by passing through the cross apertures 40 and 42 in the point 36 and thence surrounds the end of the sandwich feed and lies adjacent the edges of the meeting faces of members 50 and 52a. Such ink lying adjacent the members is sucked into the passages by capillary attraction. The ink enters the slot 70 in member 52 by virtue of capillary attraction. The ink then travels by capillary action through the sandwich feed toward the writing element and passes into the slit 72 therein from the slot 68. v

The forward end of the sandwich feed is sufficiently flexible that the spring 63 will normally urge the sandwich feed up against the nib, and will flex sufficiently to permit the nib to be removed from the feed bar for replacement or repair.

The nib is provided as shown in Figs. l and 6 with an air intake opening at 74, which extends through the nib and opens at its forward edge into the ink slit 72. The feed bar is provided with a plurality of combs 76 which form therebetween a plurality of ink overflow absorbing cells 78, which for convenience are termed the secondary ink reservoir, and which communicate with the slot 60 along the nib supporting surface of the feed bar. The cells 78 are of capillary dimension. The feed bar is provided with a shoulder 80 which is snugly received within the body 20 of the pen, and is cut away as at 82 to provide an opening therethrough. The diameter of the feed bar forwardly of the shoulder is reduced to receive the writing element 56, which extends around the feed bar and terminates short, as shown at 84 in Fig. 4, of extending completely around the feed bar. Because the nib terminates short of extending completely around the feed bar, a passage 86 is provided between the feed bar andthe pen body 20. This passage is of capillary dimension and communicates with the ink overflow cells 78, and with the aperture 82 through the shoulder 80.

The reservoir or member 48, which functions both as an air intake and as a temporary ink storage chamber, is disposed just behind the feed bar. The reservoir is shaped to provide an external helical groove or channel 88, which winds around the reservoir from one end to the other, forming la long continuous air intake passage. The spiral comb 90, which cooperates at each turn to form the helical channel, terminates at its forward end in a wall section 92. The wall 92 abuts the shoulder 94 formed in the body 20, and serves to position the reservoir axially within the body. The reservoir is received in the body in a snug ink-tight fit at the perimeter of the comb 90, such that the helical channel 88 is closed at its periphery by the encircling wall of the body. The last two turns of the helical channel are cut away as at 96 to formav slot` therethrough, shownin Figi 2. The helical channel `88 inthe reservoir is of capillary dimension, and the spacing between each turn of the helical comb 90 is constant throughout the length of the reservoir. The forward wall 92 is provided with an opening therethrough at 100. This opening provides cornmunication between the helical channel of the reservoir and the passage 86 between the feed bar and thebody. It will be noted that the rear of the feed bar is cut away as at 102 to provide a vertical slot opening at itsrupper end into the sandwich feed. receiving slot 60, and opening at its lower end into the slot 82 formed in the shoulder 80 of the feed bar.

It will be noted that the rear end of the helical channel S8 in. the reservoir opens into the space 104 within the pierce 38. Space 104 communicates with the passage 44 in the pierce, which passage surrounds the sandwich feed as hereinabove explained; Itisf now apparent that air may enter the ink storagecompartment 26 by entering the pen through the passage 86, thence through the slot 82 and into the helical channel v88 through thefopening or aperture 100 in .thewall' 92 of the reservoir. Air may travel through the reservoirv by following the turns of the helical channel until it reaches the rear endV of the reservoir from whence it passes into the space 104,- and then into the passage 44, and finally out through the cross apertures 40 and 4Z'in the pierce and directly into the storage chamber. It is also apparent that air may enter the ink storage compartment 26 by passing through the air intake opening 74 inthe nib, and passing from such opening through the sandwich feed receiving slot 60 to the vertically extending slot 102 in the rear face of the feed bar to the'slot 82 in the shoulder 80.. From this point such air travels through the reservoir to the ink storage compartment in the' manner above described.

The helical channel SSof the primary reservoir forms, as will now be appreciated, a portion of the air inlet for the ink storage compartment, this portion being a single continuous ribbon-like `and uninterrupted passageway portion which provides at least a major portion of the air intake passageway. Any air entering the ink storage compart-ment must pass through the helical channel in the reservoir. On the other hand, ink may leave the ink storage compartment through two different paths. One of these paths is through the sandwich feed, and this ink will pass toward the pen nib. The other path that the ink may travel is through the passage 44, into the space 104, and from there into the helical channel 88 of the reservoir. Such ink moves toward. the opening 100 in the forward wall92 of the reservoir. Whenever the ink storage compartment is partially full of vink and while the pen is held in a writing position, or with the nib downwardly, and the ratmospheric pressure. surrounding the pen decreases, or the air inthe ink storage compartment increases in pressure, a condition will arise in the pen which will tend to force-ink out ofthe ink storage compartment. Such condition is caused bythe air pressure in the ink storage compartment exceed-ing the air pressure 'of the 4atmosphere surrounding the pen. Such condition is frequently termed. a. flooding condition, and unless the pen is providedfwith. some means for absorbing ink which is forcedout ofthe ink. storage compartment, the pen will leak; v

It has becomeV desirable to. provide pens with rep-lace* able ink cartridges-whichwill-hold a considerably greater amount of ink than is possible withthe conventionalrubber sac type pensor the like. Pens employing thevreplaceable ink cartridgemustbeprovidedwith a greater capacity for absorbing, inkY forced from thev cartridge during the oodingcondition'than pens which employ the rubber sac or the like. This is true because the replaceable cartridge contains a greater volume of ink and consequently will hold a greater amount Vof air when the cartridge is partially exhausted. The reservoir arrangement shown in the drawings is capable of holding a substantially greater 6 amount of ink than'ispossiblewith the; conventional ink overflow grooves in use today.

In the normal operation of the pen for writing, ink from storage compartment 26 will pass through cross apertures 40 and 42 in the pierce, and pass through the sandwich feed passages 62, 64 and 66 tothe pen nib, and from thence to the writing surface. Asink is exhausted from storage compartment 26, air contemporaneously enters the compartment by way of the helical channel 88 in the primary reservoir.

To explain the operation of the pen during a flooding condition, i.e., when the air pressure in the ink storage compartment exceeds the air pressure surrounding the pen, assume for illustrative purposes that the ink storage compartment is only partially filled with ink, and that the pen is held in a position such that the writing element extends in a downwardly position. Under such conditions ink will tend to flood out of the ink storage compartment. Some of this ink will pass down Vthe sandwich feed channel 62 and ink feed passages 64 and 66 tow-ard the pen nib,gand some of the ink will enter the helical groove 88 in the primaryreservoir. That ink which passes through the sandwich feed toward the pen nib is absorbed by the ink overflow cells 78, or secondary reservoir, in the feed bar, andthe ink traveling through the passage 44 and into the space 104 is received by the helical channel 88 of the reservoir. The pasageway 44 and the helical channelV 88 are of larger wall to wall or cross sectional dimensionV thanthe feed duct 62 and the ink passages 64 and 66 of the sandwich feed. Therefore a greater amount of ink will flow into the helical channel than will flow through the sandwich feed to the pen nib. It is preferable that the relative sizes of the ink passages through the sandwich feed and the passage to the helicalv channel and the helical channel itself be soV proportioned that a substantially greater amount ofink will enter the primary reservoirv as will travel through the sandwich feed toward the pen nib. We have found that a ratio of 1:5 is satisfactory, Le., the cross-sectional areas of the passage 44 `and helicalchannel S8 are substantially five times greater than the cross-sectional areas of the feed channel 62 and passages 64 and 66 in the sandwich feed. As a result, substantially ve times as much ink will flow into the primary reservoir as will pass toward the pen nib through the sandwich feed. As the ink enters the helical' channel it follows the course of the channel along the comb 90 and moves toward the forward end of the reservoir. Normally the increase in air pressure in the ink storage compartment will be reduced to equality with the air pressure in the atmosphere surrounding the pen before the reservoir is filled with ink. Only under an extreme ditferentialin pressures between the ink storage reservoirand the atmospheric pressure will the reservoir becompletely filled with ink.

The overflow cellsy 78 comprising the secondary reservoir serve to absorb that portion of the ink iiooding from the storage compartment which passes toward the pen nib through the feed duct in the sandwich feed. The primary reservoir acts to absorb the remainder of the ink ooding from the storage compartment. Because of the relative proportions, as above mentioned, in the sizes of the feed duct and the passages to the helical channel in the primary reservoir and the size of the helical channel itself, the greater portion of this ooding ink enters the primary reservoir. The primary reservoir comprising the helical channel is adapted to holdrnorey ink than the secondary reservoir. We have found that satisfactory results may be obtained when the capacities of the two reservoirs are in the ratioof,v 5:1 which, it will be noted, is substantialiy the same as the ratioV of the passageway4 441 and the helical channel 53 is to the size of the feed duct 62 and passageways 64 and 66. It is to be understood that these ratios` may vary with various pen constructions and designs.V These two reservoirs cooperate to prevent leakage of the pen, each providing a container A7 for ink leaving the storage compartment, one absorbing it fromthe ink feed duct, the other absorbing it directly from the storage compartment. i

It maybe pointed out that the ink which passes through the sandwich feed toward the pen nib during a flooding condition in the pen leaves the sandwich feed and enters the slot 60 in the feed bar, and lies above the sandwich feed in the slot and/or between the meeting faces of the sandwich feed and the slot, as at 67 and 69 in Fig. 4. As ink continues to flood toward the nib, the ink lying in the slot moves into the capillary cells 78 in the feed bar. It is therefore apparent that the sandwich feed communicates with the capillary cells 78 in the secondary reservoir.

The reservoirs are emptied when either of two conditions occurs, namely, the ambient atmospheric pressure exceeds the pressure in the ink storage compartment, or the pen is used for Awriting. With the advent of the first condition, the atmospheric pressure reacts upon the ink in the cells 78 to urge such ink back through the sandwich feed into the storage compartment and contemporaneously urges the ink in the helical channel 88 back into the storage compartment. If the pressure differential exists for a sull'icient length of time, the two reservoirs are completely emptied, and some air may even enter the storage compartment by way of the primary reservoir. If, on the other hand, the pen is written across a writing surface, ink ows from the nib to the writing surface as the nib travels thereover. As is well known, this ilow of ink is caused by the capillary attraction of the ink in the nib to the porous surface of the paper. As the ink on the nib ilows upon the paper, it is replenished byink flowing from the cells 78 of the secondary reservoir. When the ink in the secondary reservoir is exhausted, or while it is being exhausted, ink flows from the storage compartment, through the sandwich feed to the nib. This ink flowing out of the storage compartment creates a partial vacuum in the storage compartment, viz: the pressure in the storage compartment falls below the ambient atmospheric pressure. Upon this occurrence, the atmospheric pressure urges ink in the helical channel 88 back into the storage compartment to equalize the pressure differential. The capillary attraction of the ink on the nib to the porous writing surfaces overcomes the force of gravity on the ink in the helical channel and so the ink in the channel will move upwardly against gravity and into the storage compartment.

As mentioned above,` the helical channel 88 is of capillary dimension and is of larger cross-sectional area than the passageways in the sandwich feed. Because the helical channel is of capillary dimension, ink standing in the channel will not run out of the vent opening 100 if the pen is held in a writing position. Similarly, ink standing in the channel will not separate into individual slugs of ink separated by air pockets. This latter feature of the channel ensures that, as the primary reservoir is emptied back into the storage compartment, only ink will enter the compartment until the reservoir is completely exhausted. There will be no air pockets in the ink in the reservoir which may be expelled into the storage compartment ahead of a slug of ink. The ink in the helical channel is a solid thread of ink, completely lling the channel for as far along the channel as it extends, and this thread of ink moves as a solid column of ink either toward or away from the storage compartment.

What we claim is:

1. In a fountain pen including a pen body, an ink storage chamber and a writing element, the improvement which comprises: means extending between the storage chamber and the writing element providing an ink feed duct of capillary dimension in cross-section for delivering ink to said writing element; means connected to the storage chamber providing an air intake passageway for the storage chamber vented to the atmosphere at one end and vented to the storage chamber at the other end; said air intake passageway throughout at least a major por tion of its length being a single continuous, ribbon-like and uninterrupted passageway portion and of predetermined capillary cross-sectional area, of less capillary strength than the feed duct and being isolated therefrom, to prevent air percolation through ink therein and insure movement of the ink body as a single continuous unbroken ribbon; said air intake passageway serving, when the pressure in the storage chamber exceeds that of the ambient atmosphere, to receive ink forced from the chamber and temporarily store such ink, with that ink received by said portion of the air passageway being stored as a solid unbroken ribbon, and with such ribbon being forced back toward the storage chamber through said major portion as a solid unbroken ribbon when the ambient atmospheric pressure exceeds the pressure in the storage chamber; and said air intake passageway throughout said portion and to the end of the air intake passageway vented to the atmosphere being separate from and operatively independent of the ink feed duct.

2. In a fountain pen as defined in claim 1 and said major portion of said air intake passageway winding through a plurality of turns.

3. In a fountain pen as defined in claim 1 and including accumulator means in fluid communication with the ink feed duct at said writing element, said accumulator means including a capillary cell for receiving overflow ink from the ink feed duct.

4. In a fountain pen as defined in claim 1 characterized in that said pen body is hollow and said means providing the air intake passageway includes a member received in the hollow pen body and shaped to define a helical channel constituting said single passageway portion of lthe air intake passageway.

5. In a fountain pen as defined by claim 4 further characterized in that said means providing the ink feed duct is at least partially supported by the member defining the helical channel.

6 In a fountain pen as defined by claim 1 characterized in that said pen body is hollow and has an inner wall, and said means providing the air passageway includes a member shaped to provide an external spiral comb cooperating with said wall to define a helical channel constituting said single passageway portion of the air intake passageway.

References Cited in the file of this patent UNITED STATES PATENTS 2,158,615 Wright May 16, 1939 2,401,167 Kovacs May 28, 1946 2,432,112 Lovejoy Dec. 9, 1947 2,480,718 Donato Aug. 30, 1949 2,512,004 Wing June 20, 1950 2,795,211 Nichols June 11, 1957 FOREIGN PATENTS 932,339 France Nov. 24, 1947 1,005,485 France Dec. 26, 1951 835,414 Germany Mar. 31, 1952 1,031,285 France Mar. 18, 1953 176,469 Austria Oct. 26, 1953 1,058,739 France Nov. 4, 1953 1,078,557 France May 12, 1954 

